Acetaldehyde, when heated in the presence of sodium hydroxide and $I_2$, forms:

Comment on the stereochemistry of the products for the following reaction:
$3$-methylpentan-$2$-one + $CH_3MgBr$ followed by $NH_4Cl$ workup.

What are $A, B, C$ and $D$ in the following cross-aldol condensation reaction?
$\text{Propanal} + \text{Ethanal} \xrightarrow[ii) \ \Delta]{i) \ NaOH} A + B + C + D$
(The products are the four possible $\alpha,\beta$-unsaturated aldehydes formed by self and cross-aldol condensation followed by dehydration.)

Explain the preparation of hydrocarbon compounds by the Clemmensen reduction reaction.

Consider the following reaction sequence:
$B \xleftarrow{NaBH_4} CH_2=CH-CHO \xrightarrow{H_2/Pt} A$
Identify $A$ and $B$.

Which of the following react with $NaHSO_3$?